This article intends to present different methods to calculate the concentration time (tc) and discharge in watersheds. The methods are divided into empirical and process-based and were applied to the Livramento watershed in Portugal. Due to the watershed's spatial heterogeneity and space-time variability, one suggests use of the process-based method rather than the empirical in order to achieve more accurate results, since watershed occupation does not remain the same over time. The time of concentration obtained by empirical and process-based methods are then used to compute watershed discharge through the Rational and Soil Conservation Service methods. With this procedure one can predict the impact of man-made projects on watershed hidrology. The results show that process-based methods can be useful to assess the impact of a project in hydrologic system.
Time of concentration; empirical method; process-based method; flood discharge; space-time variability
